The present invention relates generally to pixel arrays, and more particularly, it relates to an imager display pixel array which may be selectively read out in a high resolution, and a low resolution mode.
Solid state detector arrays have been developed for consumer, commercial, scientific, medical, military and industrial applications. Consumer applications range from video to high-definition television. Industrial uses include robotics and machine vision; electronics imaging for advertising in communications; integrated text; and images in office work in publishing. Image sensors are also used for medical (mammography, chest x-rays), astronomy, spectroscopy, surveillance, airport luggage inspection, inspection of foreign objects in food stuffs, non-destructive testing in industry, and many other applications.
Solid-state devices, such as photodetectors, are used for detecting electromagnetic radiation, such as x-rays, infrared radiation, ultraviolet radiation, and visible light. The photodetector stores the image momentarily, and then, after a selected time interval, converts the image to an electrical signal. The strength of the generated electrical signal corresponds to the intensity of the visible light radiation. The electrical signal is converted to digital data and stored in a memory device or electrically displayed.
One known pixel array for use in imaging devices is suggested in U.S. Pat. No. 5,336,879 entitled "Pixel Array Having Imaging Forming Pixel Elements Integral with Peripheral Circuit Elements", issued on Aug. 9, 1994 to Donald J. Sauer, the same inventor as the present application. The entire disclosure of U.S. Pat. No. 5,336,879 is herein incorporated by reference.
The resolution of the output from the imager array is dependent upon the size and number of pixel elements in the imager array. High resolution pixel arrays have a slower read-out time due to the increased number of pixel elements. It is desirable to have a high resolution imager array which may be operated in a low resolution mode for faster read out of the signal representative of the detected image.
The field of medical imaging includes fluoroscopic imaging and radiographic imaging. In radiographic imaging, very high resolution read-out is desired. In contrast, for fluoroscopic imaging, the image may be read-out in a lower resolution mode, although it is desirable to obtain an image read-out within a fast period of time. Therefore, in one particular application, it is desirable to have a pixel array for use in a medical imaging apparatus which may be read-out in a low resolution fluoroscopy mode having high frame rates, or a high resolution radiographic mode. The consolidation of a low resolution and high resolution system into a single medical imaging device provides an economical and convenient, multifaceted imaging device in a single unit.